Milton R. Young Units 1 & 2

Location: Center, N.D.

Client: Minnkota Power 

Cooperative

Completion Date: 2010 

and 2011

PROJECT SUMMARY

Burns & McDonnell is providing preliminary engineering, detailed design, field engineering support and startup 

services for the flue gas desulfurization (FGD), selective non-catalytic reduction (SNCR) and overfire air (OFA) 

retrofit projects at the Milton R. Young Station, Units 1 and 2, near Center, N.D.

SERVICES PROVIDED

 Preliminary engineering

 Technology assessment

 Detailed engineering

 Field engineering support

 Startup assistance

PROJECT BACKGROUND AND DESCRIPTION

The Milton R. Young air quality control system will be installed on Units 1 and 2 to meet the requirements of 

Minnkota Power’s consent decree with the U.S. Environmental Protection Agency. The project includes the 

addition of an FGD system on Unit 1, upgrades to an FGD system on Unit 2, the addition of lime receiving and 

preparation systems for both units, and the addition of SNCR and OFA systems to both units.

Burns & McDonnell performed a technology assessment to investigate available proven technologies that could 

meet the criteria of the consent decree for both sulfur dioxide (SO2) and nitrous oxide (NOx) emissions.

The technology selected for SO2 reduction on Unit 1 was a wet lime FGD system because it could provide the 

removal required by the consent decree at the most effective cost. The existing electrostatic precipitator performs 

well, saving the cost of a fabric filter required by dry technologies. Also, the owner was already familiar with wet 

lime technology since the existing Unit 2 FGD system uses wet lime technology.

Two new lime unloading, storage and preparation systems will be provided. Each system is capable of providing 

100 percent of the slurry necessary for both units. The system includes two new lime storage silos. Vertical ball 

mill slakers will be enclosed underneath each silo.

The existing Unit 2 FGD system uses flue gas bypass around the FGD absorbers to reheat the flue gas above 

saturation. The consent decree will no longer allow flue gas bypass. Also, the existing Unit 1 chimney is not 

suitable for wet flue gas operation. A new chimney with a FRP liner will be built for Unit 2. The existing Unit 2 

chimney will be converted to wet flue gas operation for Unit 1. This will include wall papering the liner with alloy to 

resist corrosion and adding a drain system to collect the condensate.

Modifications to the existing Unit 2 FGD system will be implemented to eliminate the flue gas bypass and 

improve the SO2 removal efficiency. The exit cones of the absorber modules will also be modified to interface 

with the new chimney and handle the increased flue gas flow resulting from no bypass.

The technology selected for NOx reduction on both units was OFA with SNCR. OFA systems were designed for 

both units. The existing lignite drying systems were modified to provide room necessary to accommodate the 

OFA ductwork. Urea solution was selected as the reagent for the SNCR. Four 60,000-gallon urea storage tanks 

in an enclosed building were designed to store, prepare and deliver the urea solution to the boiler injection ports.
Engineering, Architecture, Construction, Environmental and Consulting Solutions

The project is being performed under a multiple contract approach with Burns & McDonnell providing the detailed 

design for the balance of plant systems and integrating the various subsystems. Several contracts were used to 

procure equipment for the project including the FGD system and the SNCR system. Multiple construction 

contracts were created to complete the on-site work for the project.

Burns & McDonnell is providing a field engineering staff on-site during the project construction and is assisting 

the owner with startup.

Anticipated removal efficiencies for SO2 emissions will be 95 percent on Unit 1 and 90 percent on Unit 2. NOx

emissions will be reduced in two phases. The first phase will reduce NOx emissions using OFA by 37 percent on 

Unit 1 and by 40 percent on Unit 2. Phase two will reduce NOx using SNCR systems on both units.

The project is being constructed in multiple phases to comply with the consent decree dates and coordinate with 

planned outages. Construction began in spring 2007 and will be completed by summer 2011.

PROJECT FEATURES

 Wet lime FGD system on Unit 1

 Upgrade existing wet lime FGD system on Unit 2

 Lime receiving and preparation systems for Units 1 and 2

 SNCR systems for Units 1 and 2

 OFA systems for Units 1 and 2

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